Mass resolved excitation spectroscopy of radicals: Benzyl and phenylnitrene

Two-color mass resolved excitation spectra are obtained for the benzyl and ‘‘phenylnitrene’’ radicals. The spectrum previously assigned to the benzyl radical is generated by a species with mass 91 amu. This finding is consistent with the proposed C6H5ĊH2 benzyl radical structure. The origin of this 1 2A2←1 2A1 transition lies at 21 997 cm−1. The ionization energy for the benzyl radical is ∼7.236 eV. The phenylnitrene radical spectrum is associated with a species of 90 amu. The phenylnitrene designation is not appropriate for this mass number: the suggested cyanocyclopentadienyl radical species (C5H4CN) is consistent with this mass. This radical has an ionization threshold of ∼9.05 eV. Lifetimes are reported for a number of the vibronic states of both radicals.